Apparatus for skiving leather and the like



Nov. 17, 1970 E. H. BECK 3,540,243

APPARATUS FOR SKIVING LEATHER AND THE LIKE Filed July 10, 1968 4 Sheets-Sheet 1 av. 1?, 19'70 E. H. BECK 3,54 43 APPARATUS FOR SKIVING LEATHER AND THE LIKE Filed July 10, 1968 4 Sheets-Sheet 2 Nov. 17, 1970 E.-H. BECK APPARATUS FOR SKIVING LEATHER AND THE LIKE Filed July 1o,' 1968 4 Sheets-Sheet 5 Nov. 17, 1970 E. H. BECK 3,540,243

APPARATUS FOR SKIVING LEATHER AND THE LIKE Filed July 10, 1968 4 Sheets-Sheet 4 United States Patent 0 3,540,243 APPARATUS FOR SKIVING LEATHER AND THE LIKE Edwin H. Beck, Lemay, Mo., assignor to Manufacturers Supplies Company, St. Louis, Mo., a corporation of Missouri Continuation-impart of application Ser. No. 412,754, Nov. 20, 1964. This application July 10, 1968, Ser. No. 743,813

Int. Cl. C14b 1/22 U.S. Cl. 69-95 14 Claims ABSTRACT OF THE DISCLOSURE Apparatus for skiving leather-like materials to produce a scarf having the contour of a line of beauty (elongated S) which includes a bevel joined with an escarpment at one or both ends of the bevel to improve both the imperceptibility and strength of a joint made with matingly scarfed workpieces. The apparatus involves a bell-knife skiver in which the workpiece is fed to the knife with the to-be-beveled zone of the workpiece clamped by a presser device against the peripheral surface of the feed roll, while the adjacent to-be-escarped zone or zones of the workpiece are biased, respectively, inward over a shoulder on the feed roll, and outward about a sharpcornered tricorn toe on the presser device.

RELATED APPLICATION This application is a continuation-in-part of my application Ser. No. 412,754, filed Nov. 20, 1964, now U.S. Pat. No. 3,396,068.

The invention relates to apparatus for skiving work pieces of leather-like material to produce a scarf consisting of a bevel joined at one or both end-s by an escarpment which is, or are, substantially normal to the exterior surface, or surfaces, of the workpieces.

The object of the present invention is to provide a machine for skiving workpieces of leather, or the like, to produce a scarf of the character aforesaid, which is useful, inter alia, in the making of joints as described and claimed in the aforesaid parent application.

The apparatus of the present invention involves modification of a bell-knife skiver of the type well known in the shoe and leather-working industries to adapt the skiver to produce, in a workpiece, a scarf having a bevel which is wholly below the grain surface of the workpiece, while the grain surface is severed by an escarpment which is substantially normal to the grain surface at the outside, but, at the inside, joins the bevel' Preferably, the escarpment of the scarf has a curvature such as to merge into the adjacent end of the bevel. Such an escarpment may also be at the end of the bevel adjacent the flesh side of the workpieces, but, in any event, is at the grain side, except in those rare cases where the flesh side of the ultimate article constitutes the exterior and is exposed to view.

Specifically, the modifications in the conventional bellknife skiver necessary to enable it to produce the type of scarf aforesaid fall into the following categories:

(a) The feed roll, which is usually barrel-shaped on approximately the same radius as, and substantially aligned with, the rotatingknife, but of smaller diameter and length than the diameter of the knife, is bobbed, or otherwise provided, as by grooving, with a precipitous shoulder having a substantially radial surface which is more or less parallel with the axis of rotation of the knife, and preferably located at or near the great circle of the feed roll which is usually aligned approximately With the zenith radius of the rotating knife edge. This 3,540,243 Patented Nov. 17, 1970 "ice abrupt shoulder or escarpment permits a workpiece to be forced, while being fed toward the knife, within a virtual cylinder whose base is the orbit of the edge of the rotating knife.

(b) The presser device, usually in the form of a foot, which clamps the workpiece against the peripheral surface of the feed roll while being fed toward the knife, is modified in two particulars. First, the toe end (i.e., the end surface addressed toward the operator of the machine) makes a distinct angle (as contrasted with conventional rounding) with the bottom or workpiece clamping surface of the presser device; and the latter surface makes an acute angle with the back surface (i.e., the surface addressed toward the knife) of the presser device. Thus, the three surfaces (i.e., the clamping surface, the end surface, and the back surface) merge into a relatively sharp (as distinguished from rounded) point about which a workpiece being skived may be bent upwardly (i.e., away from the feed roll) as it approaches the knife. Secondly, the presser device is provided with a deflector adjacent that extremity of the clamping surface which is remote from the toe end thereof. Such a deflector is arranged to project inwardly (i.e., toward the axes of rotation of the knife and the feed roll) of the clamping surface, i.e., in a direction generally normal to the clamping surface of the presser device. Such a deflector is arranged to exert a biasing force against that zone of the workpiece which overhangs the escarped shoulder on the feed roll, and which zone is thus free of the clamping action between the feed roll and the aforesaid clamping surface of the presser device. The purpose of such a deflector is to bend the unclamped marginal zone of the workpiece out of alignment with the clamped zone thereof, and over the escarped shoulder of the feed roll. Such a deflector may be either resilient or rigid, but, in any event, is so located as to bend the unclamped margin of the workpiece within the aforesaid virtual cylinder projected from the knife edge, and is also so located that it does not extend beyond the plane of the knife edge where it might foul against the latter.

(0) The customary top plate, which provides a sort of worktable for positioning the workpiece in advance of its engagement by the feed roll and/or the presser device, is modified on its under-surface to provide a finger, preferably resilient, which extends above the feed roll in sufficiently spaced relationship to the toe end of the presser device to accommodate the thickness of the workpiece between them.

Such finger tends to bias a workpiece, while clamped between the feed roll and the clamping surface of the presser device, in a direction away from the feed roll and upwardly about the toe end of the presser foot, thereby to create a curve in the workpiece as it is fed toward the knife, which curve is in the opposite sense, and at the opposite end, of the scarf being made from that created by the deflector referred to in paragraph (b) above. The provision of such a finger, however, is not indispensable, as a skilled operator can manually bias the workpiece being skived upwardly about the toe end of the presser device without the aid of such a finger.

(d) The conventional edge guide is modified to provide a tongue which extends within the aforesaid virtual cylinder, i.e., below the aforesaid top plate, so as to continue to guide the edge of the workpiece being skived as the unclamped portion thereof approaches the deflector described in paragraph (b) above. This modification is not indispensable, as a skilled operator may, by exerting the proper pull on the workpiece to prevent its tendency to follow the knife edges direction of rotation, maintain the proper alignment; or a separate edge guide may be mounted on the presser device at a position behind the deflector.

Thus, it will be seen that the corelation of a driven feed roll, with a presser device which locally clamps a limited zone of the workpiece against the surface of the feed roll and drives the workpiece toward the rotating knife edge, causes the clamped zone of the workpiece to be held in substantial alignment with the aforesaid virtual cylinder, and split by the knife edge while one unclamped zone of the workpiece is being bent about the tricorn toe of the presser device, outwardly of the virtual cylinder, and while another unclamped zone of the workpiece is being bent inwardly of the virtual cylinder about the escarped shoulder on the feed roll. This mode of feeding the workpiece to the knife produces three dilferent slopes in the scarf, to wit: a bevel at the clamped zone of the workpiece, an escarpment at the zone of the workpiece outside the tricorn toe of the presser device, and a reverse escarpment at the opposite extremity of the bevel adjacent the deflector. Of course, where it is desired to have but one escarpment in the scarf (usually at the grain side), the instrumentalities for producing the escarpment at the oth er end of the bevel may be dispensed with. 3

In the accompanying drawings, one complete embodiment of the apparatus of the invention is illustrated, together with certain modified versions of the presser device, and in order to facilitate understanding of the result achieved by the apparatus, the scarf, joints made with it, and a completed leathern article including it, are shown. In the accompanying drawings:

FIG. 1 is a perspective view of a shoe whose upper is formed of a plurality of swatches joined by scarves made in accordance with the present invention;

FIG. 2 is a perspective view of a swatch of leather in the process of being skived in accordance with the present invention;

FIG. 3 is a view in side elevation of two swatches of leather skived in accordance with the present invention, one to provide the underlap, the other to provide the overlap, of a scarp-lap-joint;

FIG. 4 is a perspective view of the joint formed by the underlap and overlap shown in FIG. 3;

FIG. 5 is an exploded view of two swatches of deepgrained leather scarfed in accordance with the present invention, so as to provide an underlap and an overlap of a scarf-lap-joint;

FIG. 6 is a plan view of the obverse surface resulting from the joinder of the swatches shown in FIG. 5;

FIG. 7 is a sectional view taken along line 7,7 of FIG. 6;

FIG. 8 is a perspective view of the rotating knife, the feed roll, the presser device, the edge guide, and the top plate of a typical bell-knife skiving machine so modified and equipped as to produce scarves having the contour required to produce the scarf-lap-joint of the present invention;

FIG. 9 is a perspective view of the form of presser device in the form of a foot preferred for use in the skiving machine to produce scarves of the type shown in FIGS. 2, 3, 4, 5 and 7;

FIG. 10 is a toe-end view of the presser foot shown in FIG. 9;

FIG. 11 is a view in elevation, as seen from the edge of the knife in the skiving machine, showing the relationship between the leather being skived, the presser foot, the feed roll and adjunct devices to conform the leather to the contour which results in a scarf having the contour shown in FIGS. 2, 3, 4, 5 and 7;

' FIG. 12 is a diagrammatic elevation, viewed along the axis of the feed roll shaft toward the toe of the presser foot, of the structure shown in FIG. 11, but excluding the leather being skived;

FIG. 13 is a view corresponding to FIG. 9, but showing a presser foot modified to produce a scarf having a relatively short bevel; and

FIG. 14 is a view corresponding to FIG. 9, but showing a further modified version of a presser foot.

The shoe shown in FIG. 1 of the drawings is illustrative of a leathern article constructed in accordance with the present invention, wherein part or all of the outside surface is a composite of a plurality of swatches of leatherlike material with substantially imperceptible joints between them. The most conspicuous part of a shoe is the vamp, and in the shoe illustrated in FIG. 1, the near side of the vamp includes segments 1, 2, 3 and 4, segments 1 and 2 being joined together by scarf joints of the character hereinbefore indicated and later to be described in detail. Likewise, segment 2 is so joined to segment 3, and segment 3 is so joined to segment 4. Moreover, segment 4 of the vamp is so joined to a quarter section 5 of the upper.

While lines of demarcation 6 are shown between the respective segments of the shoe vamp, it will be understood that these are merely to designate the location of the joint between those segments, and, as previously indicated, in the finished product the joint is intended to be practically imperceptible. While all the joints at 6 are alike, the joint between segments 2 and 3 will now be described in detail by reference to FIGS. 2, 3 and 4.

Referring now to FIG. 2, there is shown a swatch of leather from which segment 2 of the shoe vamp is to be formed. The swatch is out according to a predetermined pattern to provide converging edges 21 and 22 which are shown as rectilinear, but are not necessarily so in practice. As shown in FIG. 2, the swatch is a mite wider between edges 21 and 22 than will be the ultimately scarfed segment. The difference in width is a matter of convenience in making the scarves with the apparatus hereinafter described, and is represented in FIG. 2 by a residual stripe of grain 23, about a sixteenth of an inch in width, which is integral with the scrap strip 24 resulting from the skiving operation. Having skived off the scrap 24, an overlay scarf 25 is formed on the swatch 2. The scarf 25 comes to a thin edge 26, where it intersects the grain side 27 of the swatch; and where it intersects the flesh side 28 of the swatch, the scarf forms a shoulder or escarpment 29. Edge 22 is reversely scarfed in like manner to provide an underlay scarf 30, whose shoulder or escarpment 31, comparable to 29, is at the intersection of the scarf with the grain side 27.

Similarly, another swatch is scarfed to provide segment 3 which, as shown in FIG. 3, has an underlay scarf 35 with a shoulder 39 at the intersection of the scarf with the grain side, and a feather 36 at the intersection of the scarf 35 with the flesh side. From FIG. 3, it will be apparent that the contour of the scarves is a non-reentrant reverse curve, resembling the so-called line of beauty, gradually sloping from its intersection with the grain side to its intersection with the flesh side, which intersections are a substantial distance away from each other, represented by the distance X in FIG. 3. The distance X is at least twice the thickness (represented by the distance Y in FIG. 3) of the swatch, and preferably substantially more than twice as shown, so as to provide a relatively long (in the direction of X in FIG. 3) bevel intermediate the reversely curving portions at the escarpments 29 and 39 and at the feathers 26 and 36.

The scarves 25 and 35 can be, and preferably are, made on the apparatus herein disclosed with the same setting for scarves that are to be joined together. For example, the overlay swatch 2 may be run through the skiving machine with its flesh side up, while the underlay swatch 3 may be run through the skiving machine with its grain side up.

The contour of the joint shown in FIGS. 3 and 4 is appropriate for fine-grained leathers, such as calf, kid and patent, with or without backing, but in the case of deep-grained leathers, such as alligator (natural, simulated, or synthetic) and other reptile skins, it is preferable to accentuate the escarptitude of the shoulder at the intersection of the scarf with the grain side of the leather, as will now be described with reference to FIGS. 5, 6 and 7.

It will be observed from FIGS. 5 and 7 that the shoulder 59 extends substantially normal to the surface of the leather for a depth at least about a thousandth of an inch greater than the depth of the grain, i.e., the distance between the highest peak 51 and the lowest valley 52 to be intersected by the scarf 55. Otherwise, the obliquity of the cut at the intersection 56 of the scarf with the grain surface will result in a ragged, rather than a regular line (as viewed in a direction normal to the grain side of the leather) and, when joined with the overlay 53, the location of the joint will be more discernible.

Regardless of the character of leather or leather-like material employed, or the depth of its grain, the contour of the scarf, such as 35, or 55, on the underlap is a reverse curve, wherein adjacent the intersection of the scarf with the grain side, or other obverse surface of the material, the slope is such that for a depth substantially less than half the thickness (Y) of the leather, the increments (d) of X are less than the increments (d) of Y; but in the case of deep-grained leather, the increments (dX) of X, equal or approach zero, at least for the depth of the grain. For the major part of the distance X, however, the slope of the curve is such that increments (dX) of X are greater than increments (dY) of Y.

Scarves of the character aforesaid can be made with facility upon a conventional bell-knife skiver so modified as to cause the swatch being skived to be biased downwardly about the end of the active surface of the feed roll, and also biased upwardly about the toe end of the presser foot. That is to say, the leather being skived is delivered to the rotating knife edge immediately upon being released from confinement wherein it was reversely curved in greater degree but in the same fashion as the curvature of the scarf desired. To accomplish this result, a conventional bell-knife skiving machine, having rotating knife 60, with a circular edge 61 driven in rotation, in the direction indicated by the arrow thereon in FIG. 8, about the axis of the circular knife edge, is provided, in accordance with the usual practice, with a feed roll 62 driven in rotation on a shaft 63 in the direction indicated by the arrow thereon (FIG. 8) about an axis which extends normal to the direction of the axis of rotation of the knife 60. Such a machine is conventionally equipped with a presser device, shown in the form of a foot, for clamping the zone of the leather or leather-like workpiece, where the bevel like 25 or 35 is to be made, against 4 the zenith of the feed roll in order that the feed roll may grip it and advance the workpiece toward, against, and over knife edge 61. One form of such a presser device, as modified in accordance with the present invention, is shown at 64 in FIG. 8. Enclosing the knife (except for increments proximate the zenith thereof), as well as the feed roll (except for increments proximate the zenith thereof), is a suitable casing including a top plate 65, on which is adjustably mounted an edge guide 66.

In the form shown in FIGS. 8, l1 and 12, the conventional feed roll 62 is bobbed at its great circle so that the maximum diameter of the feed roll is at scarped end 67, and is aligned approximately with the zenith radius of the rotating knife edge 61, as shown in FIG. 11, thereby providing an abrupt planar shoulder or escarpment over which the workpiece 7 being skived can be bent downwardly, as shown at 8.

The presser device has a toe end 68 which makes a distinct angle (as contrasted with conventional rounding) with the clamping surface 69 thereof; and the clamping surface 69 makes an acute angle with the back surface 70 thereof. Thus, the three surfaces 68, 69 and 70 merge into a relatively sharp (as distinguished from rounded) tricorn point about which a workpiece being skived may be bent upwardly (i.e., away from the feed roll) as shown at 9 in FIG. 11. By relatively sharp tricorn point is meant macroscopic rather than microscopic sharpness because the sharpness should not be of such degree as to macroscopically scratch, much less cut,

the grain surface of the workpiece moving under it; and to maintain such macroscopic sharpness during prolonged use, it is desirable to provide a tungsten carbide tip on the tricorn toe. As clearly shown in FIGS. 9 and 11, the clamping surface 69 is arcuate to substantially match the arcuity (in the plane shown in FIG. 11) of the feed roll 62 and the knife edge 61. The length (parallel with the the orbit of the knife edge as shown in FIG. 11) of the clamping surface 69 is preferably short, i.e., no greater than the length (X) of the scarf to be made, but at least as long as the bevel portion of the scarf; and the clamping surface preferably terminates at the zenith line of the feed roll so that at least the toe end of back surface 70 is radially aligned with the axis of shaft 63. The presser device is also provided with a deflector 71 shown in the form of a leaf spring, the free end 72 of which (when unstrained) projects below the edge formed by the intersection of surfaces 69 and 70, as shown clearly in FIG. 10, for the purpose of biasing the unclamped margin of the workpiece 7 over the scarped end of the feed roll, i.e., inside the aforesaid virtual cylinder, to create the curve as shown at 8 in FIG. 11. However, during the skiving operation, the leaf spring 71, or at least the extremity thereof nearest clamping surface 69 yields so that the free end 72 approaches said intersection (as shown in dotted lines in FIG. 10), but does not extend beyond the plane of the back surface 70 where it might foul against the knife edge. In operating relationship, the free end 72 of the deflector is spaced at least a workpiece thickness from the shoulder 62 on the feed roll, but the more distant said free end is positioned away from shoulder 62, the greater will be the radius of curvature of curve 8, and the greater will be the radius of curvature at scarf edges 26 and 36.

The usual top plate is modified on its under-surface to adjustably accommodate a spring finger 73 having a free end, which extends above the feed roll in closely spaced relationship to the toe end 68, and thus tends to bias a workpiece passing over it upwardly (i.e., outwardly of the aforesaid virtual cylinder) about the toe end of the presser foot to create the curve shown at 9. The free end of spring finger 73 is spaced at least a workpiece thickness from the toe end 68, but the greater the spacing, the greater will be the radius of curvature of curve 9, and the greater will be the radius of the scarf at shoulders 29 and 39. Spring finger 73 is not indispensable, as a skilled operator can manually bias the leather being skived upwardly about the toe end of the presser foot without the aid of spring finger 73.

An edge guide 66 is adjustably mounted on top plate 65 as usual, but the invention contemplates that such edge guide be provided with a tongue 81 which projects heneath the presser foot so as to continue to guide the edge of the workpiece being skived as it is biased downwardly (i.e., inside the aforesiad virtual cylinder) by deflector 71. This feature is not indispensable, as a skilled operator may, by exerting the proper pull on the swatch to prevent its tendency to follow the knife edges direction of rotation, maintain the proper alignment. The curvature on the upper side of tongue 81 is similar to that of the deflectors free end 72, and while they do not necessarily touch, it is preferable that the tongue 81 does not substantially flex deflector 71.

As is conventional in such machines, the feed roll 62 is provided with a knurled surface circular in cross-section, but of diminishing diameter from its great circle toward its smaller end. The rate of diminution of the diameter is such as to make the radius of curvature 74 in the axial direction substantially the same as the radius of curvature of knife edge 61 (i.e., the same as the radius of the aforesaid virtual cylinder). The axis of shaft 63 is so disposed that, at its zenith, feed roller radius 74 is parallel with, and spaced from, the orbit of the knife edge 61 a distance less than the thickness of the workpiece being skived.

In the embodiment shown in FIG. 9, the presser foot is further provided with a depression 76, within which deflector 71 is accommodated at the side thereof remote from knife 61; and the presser foot is provided with a groove 77 extending horizontally and accommodating a slide bar 78 upon which deflector 71 is replaceably mounted by screw 79. To secure the slide bar 78 against movement within groove 77 (except when'it is Undergoing adjustment), any suitable means may be employed as, for example, a clamping screw extending through the back side of the presser foot.'T-hus; the'arrangement provides for adjustment of deflector 71 toward and away from toe end 68 of the pre'sser'foot within the limits of the width of depression 76, thereby to vary the slope of the scarf at its-feather end'accor'di'ng'tothe rule that the closer spring end 72 is to the end of feed roll 62, the steeper will be the feather.

The'spring finger 73 has its terminal portion (nearest knife edge-61) bent upwardly (i.e., outside the aforesaid virtual cylinder) at 80, as shown in FIGS. 8 and 12, and is accommodated in a raceway in the lower surface of the top plate 65 so that finger 73 may be adjusted both toward and away from knife edge 61, and toward and away from toe end 68 of the presser foot, in order to accommodate material of differing thickness and physical properties. The other terminal end (i.e., remote from knife edge 61) of spring finger 73 projects beyond top plate 66 in order to provide an accessible portion for manipulation of the spring finger in accomplishing the desired adjustment.

As indicated previously, the length (parallel with X) of the beveled portion of the scarf depends upon the length of the clamping area on the presser device, whereas the slope at feather 26 or 36 depends upon the escarptitude between the deflector and the clamping surface. Accordingly, the presser device of the invention may be modified in various ways to meet the requirements of its intended use. FIG. 13 shows one such modification for making a scarf having a bevel whose length is about a fourth of that produced by the presser device shown in FIG. 9. The essential difference lies in the length of the clamping surface. Whereas in FIG. 9 the length of clamping surface 69 is intended to be about long, the comparable clamping surface 169 of FIG. 13 is only 7 long. Whereas in FIG. 9 the deflector 72 is resilient and is adjustable relative to the clamping surface in the direction substantially parallel with the length of the clamping surface, in FIG. 13 the deflector is rigid, and is adjustable in the direction substantially normal to the clamping surface 169, but their relationship is fixed in the respect that they are not relatively adjustable in the length direction of the clamping surface. On the other hand, in

the form shown in'FIG. 13, the workpieceengaging parts 169 and 172 are mounted on the body of the presser device 164 so as to be adjustable as a unit in the direction substantially parallel with the clamping surface 169. As in the embodiment shown in FIG. 9, the clamping surface 169 terminates in a relatively sharp tricorn toe 165, the deflector has a sloping surface addressed toward the approaching workpiece, and the tip of the deflector is disaligned (at least to a degree equal to the thickness of the workpiece) with the clamping surface so as to cam the unclamped margin of a workpiece inwardly of the aforesaid virtual cylinder and thereby produce the curve shown at 8 in FIG. 11. The greater the disalignment between the tip of the deflector and the clamping surface, the lesser the radius of curve 8 and of feather 26 or 36.

Referring now to FIG; 14 for a further modified version of the presser'device for making a scarf having a bevel of intermediatelength, the presser foot 264 has a toe end wall 268, and a bottom wall 269 which constitutes the clamping surface. As in the previous embodiments, walls 268 and 269'intersect with each other and with back wall 270 to form a relatively sharp (as distinguished from rounded) apex or toe 265, addressed toward the knife edge 61 in the same relationship as that illustrated in FIG. 8. The line of intersection between Wall 268 and clamping surface 269, as well as the line of intersection between clamping surface 269 and back wall 270, are also relatively sharp, as distinguished from rounded, and to maintain the sharpness of thesecorners, as well as the apex or toe, it is desirable that these corner areas be provided in the form of a hard material, such as a tungsten carbide tip. The presser device shown in FIG. 14 has a deflector 271, which is rigid and adjustable in the direction substantially normal to clamping surface 269. It will be observed that the end 272 of deflector 271 is substantially disaligned with, and has a reverse slope in relationship to, the arcuity of clamping surface 269, so that the end 272 deflects an unclamped portion of a workpiece out of alignment with clamping surface 269 at the end of the latter remote from toe end268. In the position of deflector 271 shown in FIG. 14, the edge of the deflector adjacent clamping surface 269 does not provide an abrupt change of elevation such as that provided by free end 72 (when unstrained) of deflector 71 in FIG. 9,'but such abrupt change in elevation is obtainable with the presser device shown in FIG. '14 by adjusting it downwardly (as seen in FIG. 14) relative to camping surface 269.

If desired, and in place of the tongue 81'on edge guide 66, the presser feet shown in the drawings may be equipped with an edge guide as taught in my Pat. No. 3,- 133,434, and the tongue 81 thereby dispensed with.

From the foregoing description, it should be apparent that the invention accomplishes its objects, and provides an apparatus for making such scarves of the character described.

While apparatus has been herein disclosed in the forms which are believed to be best for the most general application, it is realized that the disclosed apparatus is 'susceptible of numerous modifications and variations which will not depart from the principles of the invention as hereinbefore described, and consequently it is to be distinctly understood that the invention is not limited to the details of the apparatus specifically disclosed herein for the purpose of illustrating the best form of the invention.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. Apparatus for skiving a leather-like workpiece to produce a scarf having the contour of a non-re-entrant reverse curve comprising a knife having an edge moving in a fixed path,'a feeder having a surface for engaging one side of a workpiece to move it edgewise toward the edge of said knife, a presser having a surface radially aligned with said surface of said feeder for contacting the opposite side of said workpiece to clamp the same into gripping engagement with said feeder, and means on the presser axially displaced from said surface of said feeder to bias the workpiece in the same direction as, but at least a workpiece thickness farther than, said surface of the presser, said last-mentioned means adapted to be spaced about a workpiece thickness from said feeder surface in the direction normal to said movement of said workpiece. p

2. Apparatus for skiving leather to produce a scarf having the contour of'a non-reentrant reverse curve comprising a knife having an edge moving in a fixed path,a feeder forengaging one side of a workpiece to move it edgewise toward the edge of said knife, a presser having an area for contacting the opposite side of said workpiece to press the same into gripping engagement with said feeder, meanson the presser at one end ,of' said area to biasthe workpiece in the same direction as, but in greater degree than, said area of thepresser, said last-mentioned means adapted to be spaced about a workpiece thickness from the adjacent feeder, and resilient means at the opposite end of said presser area for biasing the workpiece in the opposite direction. from said presser, said resilient means being spaced at least a workpiece thickness from the proximate portion of said presser area.

3. In a bell-knife skiver having a feed roll with a conoidal surface and an end face perpendicular to the axis of said conoidal surface, said feed roll being adjacent the edge of said knife, and a presser foot for biasing work against the conoidal surface of said feed roll, the improvement which comprises, said presser foot having a limited work-engaging surface substantially complemental with the conoidal surface of said feed roll and terminating in an acutely pointed relatively sharp toe addressed counter to the direction of movement of said knife and located at the side of said presser proximate said knife, said surface inclining upwardly from said toe in the direction away from said knife.

4. In a bell-knife skiver having a feed roll adjacent the edge of said knife, and a presser foot for biasing work against the feed roll, the improvement which comprises, said presser foot having a limited work-engaging surface terminating in an acutely pointed toe addressed counter to the direction of movement of said knife and located at the side of said presser foot proximate said knife, said surface inclining upwardly from said toe in the direction away from said knife, and a spring mounted on said presser foot adjacent the end of said surface remote from said toe, said spring normally projecting beyond said surface in the direction of the axis of said feed roll and being spaced from the end of the feed roll a distance sufficient to permit passage of the workpiece therebetween.

5. The combination of claim 4 wherein said spring is adjustable toward and away from said toe.

6. A skiving machine comprising a tubular knife rotating about an axis generally parallel with the direction in which Work is moved against the blade of the knife, a feed roll rotating about an axis substantially normal to said direction, said feed roll being located so that the zenith of its work-engaging surface has its maximum diameter substantially aligned with the zenith of the knife blade, said feed roll having a radial escarpment sharply reducing the diameter of its work-engaging surface at one side of said zenith, means having a short work-contacting area terminating at the zenith line for pressing work downwardly against the work-engaging surface of said feed roll at the opposite side of said zenith from said escarpment, and means projecting below the knife edge beyond said escarpment for pressing work below the level of the zenith of the feed roll.

7. A skiving machine comprising a circular-bladed knife rotating about an axis generally parallel with the direction in which a workpiece is moved against the blade, a feed roll rotating about an axis substantially normal to said direction, said feed roll being located so that the zenith of its surface is substantially aligned with the zenith of the knife blade, limited area means for pressing a limited zone of the workpiece downwardly against the zenith of said feed roll, means aligned in the direction parallel with the direction of blade movement with said limited area means and located on opposite sides of the zenith of said knife blade for biasing work above the level of said limited area means on one side of the zenith, and below the level of said limited area means on the other side of the zenith when the latter is pressing work against said feed roll.

8. Apparatus for skiving a workpiece of leather or the like to produce a scarf having a curved escarpment adjacent its grain side, said escarpment merging into a bevel located below the grain of said work piece and said bevel having a substantially lesser slope than said escarpment, comprising in combination:

(i) a rotating knife having a circular edge which,

projected axially, defines a virtual cylinder;

(ii) a feed device having a workpiece engaging surface curved on substantially the same radius as said knife edge and having an escarped shoulder extending substantially parallel with the axis of and with a diameter of said virtual cylinder, said workpiece engaging surface being substantially congruous with part of said virtual cylinder;

(iii) means mounting and driving said feed means in a direction such that an engaged workpiece is driven toward said knife edge;

(iv) means having a clamping surface for pressing a workpiece against the workpiece engaging surface of said feed device, said means being located in substantial part outside said virtual cylinder and having means projecting inside said virtual cylinder adjacent:

(a) one end of said clamping surface; and

(b) the escarped shoulder on said feed device; for forcing a portion of said workpiece overhanging said escarped shoulder into a position substantially inside said virtual cylinder; and

(v) means on the outside of said virtual cylinder and adjacent the other end of said clamping surface for biasing another part of said workpiece outwardly from said virtual cylinder.

9. A presser device for use in making a reversely curved scarf in a leather-like workpiece, comprising: a member having a bottom wall, an end wall, and a back wall, said walls intersecting each other to define a relatively sharp tricorn point at which the line of intersection between said end wall and said back wall makes an acute angle with both:

(a) the line of intersection between said bottom wall and said end wall; and

(b) the line of intersection between said bottom wall and said back wall;

the area of the bottom wall included between said lines of intersection (a) and (b) forming a workpiece clamping surface having a length, parallel with said line (b), no greater than the length of the scarf to be made.

10. The presser device of claim 9 having means adjacent said workpiece clamping surface and at the end thereof remote from said line of intersection (a) for deflecting a workpiece engaged by said clamping surface in a direction away from said clamping surface.

11. A presser device for use in making a reversely curved scarf in a leather-like workpiece comprising, a member having an end wall and a bottom wall, said bottom wall including a clamping surface adapted to clamp a portion of a workpiece while being scar'fed, said clamping surface extending from said end wall to a position remote therefrom a distance no greater than the length of the scarf to be made, and means for forcing an unclamped portion of the workpiece in the direction normally away from said clamping surface, said means being at least as remote from said end wall as is said position.

12. The presser device of claim 11 in which said means has a workpiece engaging surface disposed in disalignment with said clamping surface, said disalignment being in the direction normally outward of said bottom Wall and in an amount at least equal to the thickness of said workpiece,

13. The presser device of claim 12 wherein said means is adjustable in a direction substantially parallel with said clamping surface.

14. The presser device of claim 11 in which said workpiece engaging surface slopes outwardly and away from said clamping surface to a maximum disalignment which is at least equal to the thickness of the workpiece.

References Cited UNITED STATES PATENTS 946,844 1/1910 Keats 69-9.5 1,210,082 12/1916 Klager 699.5 1,247,780 11/ 1917 Alexander 69-95 1,469,850 10/ 1923 Ricks et al. 69-95 3,043,126 7/1962 Beck 69-95 ALFRED R. GUEST, Primary Examiner 

